A common type of connector includes a main part comprising a shell, an insulator within the shell, and contacts within the insulator. The front ends of the contact mate with contacts of a mating connector device, while the rear ends of the contacts are connected to wires of a cable that extends rearwardly from the main part. A coupling nut extends around the front end of the shell and secures the main part to the mating connector device, to assure proper mating and to prevent the connector and connector device from separating. In some applications, the cable may be pulled with a force that is large enough to tear it loose from the connector, while possibly tearing out parts of the connector such as the contacts from the insulator. Among actual incidents involving seismic connectors, is one wherein a truck driver drove off with the cable attached to the truck and tore the cable out of the connector, and another incident where a cable extended across a road and became caught on a passing vehicle which tore it out of the connector.
Breakaway devices have been known in the past, but applicant does not know of any breakaway connector. U.S. Pat. No. 4,909,761 describes a breakaway fuse holder wherein a nut has a rear end threadably mounted on one part and a front portion forming fingers with front ends received in a groove of a second part. When the parts are pulled apart with sufficient force, the fingers deflect radially out of the groove to release the parts. Such a construction results in the nut having slots between the fingers, which is often unacceptable in electrical connectors because electromagnetic energy may pass through such slots to interfere with signals passing between the contacts. Also, the cost of the nut would be relatively high because of the need to machine it with fingers that will breakaway at a predetermined force level. A breakaway connector of the type that includes a plurality of signal-carrying contacts, which retained the EMI (electromagnetic interference) shielding of a coupling nut or part while enabling breakaway at a predetermined force level in a construction of only moderate cost, would be of value.